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EP 2 211 939 B1 |
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EUROPEAN PATENT SPECIFICATION |
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Mention of the grant of the patent: |
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19.12.2018 Bulletin 2018/51 |
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Date of filing: 26.11.2008 |
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International Patent Classification (IPC):
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International application number: |
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PCT/EP2008/009999 |
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International publication number: |
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WO 2009/068250 (04.06.2009 Gazette 2009/23) |
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DRUG DELIVERY DEVICE WITH SHAPE MEMORY ACTUATOR, LEAD SCREW AND RATCHET MECHANISM
INFUSIONSPUMPE MIT FORMGEDÄCHTNIS-ANTRIEB, SPINDEL UND RATSCHENMECHANISMUS
DISPOSITIF D'ADMINISTRATION D'UN MÉDICAMENT COMPORTANT UN ACTIONNEUR À MÉMOIRE DE
FORME, UNE VIS-MÈRE ET UN MÉCANISME À CLIQUET
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Designated Contracting States: |
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AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MT NL NO PL
PT RO SE SI SK TR |
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Priority: |
29.11.2007 US 946905
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Date of publication of application: |
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04.08.2010 Bulletin 2010/31 |
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Proprietors: |
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- Roche Diabetes Care GmbH
68305 Mannheim (DE) Designated Contracting States: DE
- F. Hoffmann-La Roche AG
4070 Basel (CH) Designated Contracting States: AT BE BG CH CY CZ DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MT NL NO PL PT RO SE SI SK TR
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Inventors: |
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- DE POLO, Marco. C.
San Mateo, CA 94403 (US)
- WIEGEL, Christopher
Sunnyvale, CA 94086 (US)
- ROE, Steven, N.
San Mateo, CA 94403 (US)
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Representative: Rentsch Partner AG |
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Bellerivestrasse 203
Postfach 8034 Zürich 8034 Zürich (CH) |
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References cited: :
WO-A-93/07922 WO-A-2004/009160 WO-A-2006/104806 WO-A1-2007/107786
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WO-A-02/100469 WO-A-2004/056412 WO-A-2006/105792 US-B1- 6 242 841
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Note: Within nine months from the publication of the mention of the grant of the European
patent, any person may give notice to the European Patent Office of opposition to
the European patent
granted. Notice of opposition shall be filed in a written reasoned statement. It shall
not be deemed to
have been filed until the opposition fee has been paid. (Art. 99(1) European Patent
Convention).
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FIELD OF THE INVENTION
[0001] The present invention is related to drug delivery devices, and in particular to a
drug delivery device that includes a single shape memory alloy wire actuator drive
to advance a lead screw via a ratcheting mechanism.
BACKGROUND OF THE INVENTION
[0002] Shape memory alloy (SMA) actuators are used for a wide range of applications. One
typically application for SMA actuators is to perform limited displacements which
generate work. In such displacement applications, the SMA actuator is typically in
the form of a wire that transforms linear motion into incremental relative motion.
When applying a current to the cold (low temperature or martensitic state) shape memory
alloy (SMA) wire the temperature rises until the transformation temperature is reached
(high temperature or austenite state) and due to a crystalline restructuring of the
material, a contraction occurs. With such a contraction, force or torque is thus generated.
However, it is to be appreciated that after the contraction, the SMA wire does not
reset itself and therefore a counterforce has to bring the SMA wire into its original
position.
[0003] In the field of drug delivery devices, prior art drug delivery systems which use
shape memory alloy actuators are typically reset by having opposed SMA wires. Such
a configuration allows higher cycle frequencies. However, such a design is more complex
and additional space is required for the second SMA wire.
SUMMARY OF THE INVENTION
[0004] It is against the above background that the present invention provides a drug delivery
device that includes a single shape memory alloy wire actuator to advance a lead screw
via a ratcheting mechanism which provides for a more compact and less complicated
design.
WO 2006/104806 discloses a drive system for a fluid delivery device with a syringe-type container,
having a plunger that is displaced within the syringe container to deliver fluid.
The plunger, having a threaded rod, is axially displaced in a single direction. The
threaded rod is driven in the axial direction by a drive wheel having threads interacting
with the threaded rod, and being rotationally mounted on the chassis of the device.
The drive wheel is incrementally rotated in one direction by a ratchet type actuation
system. A pivotable drive engaging member comprises two pawls, which alternatingly
engage with the teeth of two ratchet wheels of the drive wheel, thereby incrementally
rotating the drive wheel. The necessary pivotal motion of the pivotable drive engaging
member is achieved by two shape memory wires that are attached to the member and are
alternatingly contracted by heating them with electric current running from one end
of the wire, fixed to the chassis, to the other end, which is attached and electrically
connected to the pivotable drive member. Instead of two separate wires, one single
wire can be used, with the electrically conducting drive member being crimped to the
wire. Also in that case, only one portion of the wire is part of the electric circuit,
while the other portion remains disconnected.
WO 2004/056412 shows a syringe-type pump drive with a unidirectionally rotatable ratchet wheel with
threads interacts with a threaded plunger rod to axially displace the plunger within
the syringe container. One spring loaded pawl prevents the ratchet wheel from rotating
in the wrong direction. A second spring loaded pawl is actuated in the drive direction
by a contracting SMA wire, rotating the ratchet wheel by one tooth. The SMA wire is
reset by a spring.
WO 2004/009160) discloses a drive system for infusion pump, with a ratchet mechanism actuating the
plunger of a cylinder pump. The ratchet mechanism comprises a ratchet wheel on a power
output shaft, which is incrementally rotated by spring acting on a pawl. The spring
is reloaded by an SMA wire. A spring loaded second pawl prevents the ratchet wheel
to rotate in the wrong direction.
[0005] In a first embodiment, a drive system used to dispense a liquid drug from a drug
container having a plunger is disclosed. The drive system comprises a lead screw having
a rotational axis and operably connected to the plunger. A ratcheting mechanism having
first and second ratchet wheels provided along the rotational axis is also provided.
The first ratchet wheel is connected to the lead screw to move the lead screw. A shape
memory alloy wire is operably connected to the second ratchet wheel and configured
to drive incrementally the rotation of the second ratchet wheel via a contraction,
which in turn drives the rotation of the first ratchet wheel about the rotational
axis which moves the lead screw and advances the plunger to dispense the liquid drug
from the drug container.
Such a drive system can comprise a controller electrically connected to the shaped
memory alloy to generate the contraction of the shaped memory alloy wire. Particularly
it can comprise a controller electrically connected to the shaped memory alloy, and
having capacitors for storing a charge used by the controller to generate the contraction
of the shaped memory alloy wire. The drive system can also comprise a hard stop mechanism
electrically connected to the controller and configured to provide motion feedback
of the ratchet mechanism.
[0006] In a second embodiment, a method of dispensing a liquid drug from a drug container
having a plunger is disclosed. The method comprises operably connecting to the plunger
a lead screw having a rotational axis, and providing along the rotational axis a ratcheting
mechanism having first and second ratchet wheels. The first ratchet wheel is connected
to the lead screw to move the lead screw. The method further includes operably connecting
a shape memory alloy wire to the second ratchet wheel, and driving incrementally the
rotation of the second ratchet wheel via contracting the shaped memory alloy wire
to drive the rotation of the first ratchet wheel about the rotational axis which moves
the lead screw and advances the plunger to dispense the liquid drug from the drug
container.
In such a method the first and second ratchet wheels can provide two opposing ratcheting
surfaces with facing axial extended teeth, said method further comprising using a
torsion spring to spring bias the two opposing ratcheting surfaces for proper engagement
of the facing axially extended teeth, and to reset the shape memory alloy wire after
the contraction driving incrementally the rotation of the second ratchet wheel.
Alternatively such a method can further comprise providing a sliding mechanism with
a S-curve shaped slot, fitting a pin of the ratchet mechanism into the slot of the
sliding mechanism, using the shaped memory alloy wire to drive the sliding mechanism
parallel to the rotational axis such that the S-curve shaped slot displaces the pin
angularly about the rotational axis, thereby causing the rotation of the ratchet mechanism,
and the incremental axial advancement of the lead screw.
[0007] These and other features and advantages of the invention will be more fully understood
from the following description of various embodiments of the invention taken together
with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The following detailed description of the various embodiments of the present invention
can be best understood when read in conjunction with the following drawings, where
like structure is indicated with like reference numerals and in which:
FIG. 1 is a partially exploded, perspective view of a drug delivery pump drive embodiment
using a single shape memory alloy wire actuator to advance a lead screw via a ratcheting
mechanism having a torsion spring which provides tight engagement between facing ratcheting
surfaces and a reset function according to the present invention;
FIG. 2 is a partially exploded, perspective view of another drug delivery pump drive
embodiment using a single shape memory alloy wire to advance a lead screw via a ratcheting
mechanism having a torsion spring which provides tight engagement between facing ratcheting
surfaces and a spring providing a reset function according to the present invention;
FIG. 3 is a partially exploded, perspective view of a drug delivery pump drive embodiment
using a single shape memory alloy wire attached to a slotted sliding mechanism which
advances a lead screw via a ratcheting mechanism according to the present invention;
FIG. 4 is a partially exploded, perspective view of another drug delivery pump drive
embodiment using a single shape memory alloy wire to advance a lead screw via a ratcheting
mechanism according to the present invention; and
FIG. 5 is a perspective view of a miniature drug delivery pump embodiment using a
drug delivery pump drive using a single shape memory alloy wire to advance a lead
screw via a ratcheting mechanism to advance a syringe plunger to deliver a liquid
drug according to the present invention.
DETAILED DESCRIPTION
[0009] In the following description of the embodiments of the invention, skilled artisans
appreciate that elements in the figures are illustrated for simplicity and clarity
and have not necessarily been drawn to scale. For example, the dimensions of some
of the elements in the figures may be exaggerated relative to other elements to help
to improve understanding of embodiment(s) of the present invention. Accordingly, the
drawings are merely schematic representations, intending to depict only typical embodiments
of the invention, and therefore should not be considered as limiting the scope of
the invention. The invention will be described with additional specificity and detail
through the accompanying drawings. The description of the invention may contain, for
example, such descriptive terms as up, down, top, bottom, right or left. These terms
are meant to provide a general orientation of the parts of the invention and are not
meant to be limiting as to the scope of the invention.
[0010] FIG. 1 is a partially exploded perspective view of a first embodiment of a drug delivery
pump drive 100 that includes a single Shape Memory Alloy (SMA) wire 10. It is to be
appreciated that such a drug delivery pump drive 100 is suitable for use in an infusion
pump application to accurately pump a liquid drug. In one embodiment, the pump drive
100 has a 3.5 x 3.5 x 15 mm footprint, which is about 20% the size of conventional
electrical micro-motors.
[0011] In the illustrated embodiment of FIG. 1, the SMA wire 10 is connected to a ratcheting
mechanism, generally indicated by symbol 12, which in turn is connected to a lead
screw 14. In one embodiment, the ratcheting mechanism 12 comprises first and second
ratchet wheels 16, 18 having facing ratcheting surfaces 20, 22 arranged perpendicularly
to the lead screw 14. As shown, the first ratchet wheel 16 is fixed to the lead screw
14, and the second ratchet wheel 18 is mounted rotatably to a post 24. As shown, the
post 24 extends through the second ratchet wheel 18 and is accommodated at an end
26 in a cavity 28 of the first ratchet wheel 16. In this manner, the first ratchet
wheel 16 is also rotatable mounted to the end 26 of the post 24. The post 24 at the
other end is fix, such as, to a base 30 of an infusion pump 32.
[0012] In one embodiment, the facing ratcheting surfaces 20, 22 are opposing axially extended
teeth, such that rotation in a first (drive) direction, indicated by arrow D, the
teeth of both ratchet wheels 16, 18 mesh and rotate together, and in a second (return
or reset) direction, indicated by symbol S, the teeth of the second ratchet wheel
18 slip or rides over the teeth of the first ratchet wheel 16, such that second ratchet
wheel 18 rotates relative to the first ratchet wheel 16 about a rotational axis, indicated
by symbol X. Accordingly, the ratcheting mechanism 12 provides a unidirectional ratchet
like motion, which rotates the lead screw 14 about the rotational axis X in only the
first direction D.
[0013] In the illustrated embodiment of FIG. 1, a torsion spring 34 is provided to the post
24 to performs two functions simultaneously, which helps to facilitate a very compact
infusion pump design. The first function of the torsion spring 34 is to provide an
axial spring force that is applied to the second ratchet wheel 18. The axial spring
force is indicated by arrow Z, and maintains a tight engagement between the surfaces
20, 22 of the ratchet wheels 16, 18 in the first (drive) direction D, but which can
be overcome in the second direction S via a resetting force, which is discussed hereafter,
to permit disengagement between the facing ratcheting surfaces 20, 22 along the rotational
axis X, thereby allowing the unidirectional ratchet like motion.
[0014] The second function simultaneously provided is that the torsion spring 34 acts as
a reset mechanism to reset the SMA wire 10 after a contraction, indicated by symbol
C, which rotates the lead screw 14 about the rotational axis X. In particular, the
torsion spring 34 stretches the SMA wire 10 back to an original (initial) position
via applying a resetting force, which is indicated by symbol R. The resetting force
R is provide via a first end (or portion thereof) of the torsion spring 34 being connected
to the second ratchet wheel 18, and a second end (or portion thereof) of the torsion
spring 34 being mounted to the post 24. Accordingly, rotation of the second ratchet
wheel 18 in the first (drive) direction D, which also rotates the first ratchet wheel
16 in the same direction, causes the ends of the torsion spring 34 to move (twist)
relative to each other, thereby loading the torsion spring 34 with torque. In this
manner, upon removal of the excitation to the SMA wire 10, the torque of the torsion
spring 34 counter-rotates the second ratchet wheel 18 about the post 24, thereby returning
the SMA wire 10 to its initial (pre-contraction) position.
[0015] As shown by FIG. 1, the SMA wire 10 is electrically connected at both ends to a controller
36 via electrical conductors 38. In use, the application of a drive signal 40, such
as for example, a current pulse from the controller 36, via the electrical conductors
38, causes the SMA wire 10 to contract due to excitation from the martensitic state
to the austenite state. This contraction C causes the second ratchet wheel 18 as well
as the first ratchet wheel 16 to rotate incrementally in the first (drive) direction
D about the rotational axis X.
[0016] As the first ratchet wheel 16 of the ratcheting mechanism 12 is fixed to the lead
screw 14, rotation of the ratcheting mechanism in the first (drive) direction D causes
the lead screw 14 to also rotate about the rotational axis X. It is to be appreciated
that the lead screw 14 is only free to rotate and is prevented from translating axially.
[0017] A threaded nut 42 engages the lead screw 14. The threaded nut 42 is provided with
a projection or key portion 44 which is situated in a slot or keyway 46 that is mounted,
for example, to the base 30 of the infusion pump 32, both of which are illustrated
in block diagram for ease of illustration. In this manner, the threaded nut 42 is
prevented by the keyway 46 from rotating about the rotational axis X with the ratcheting
mechanism 12 and lead screw 14 in the first direction D, but is free to translate
incrementally along axis X. The incremental advancement of the threaded nut 42 along
the keyway 46 causes a plunger 48 to be pushed into a syringe-like drug cartridge
or container 50. The pushing of the plunger 48, via incremental advancement of the
threaded nut 42, causes a liquid drug to be expelled from the container 50 in a controlled
manner.
[0018] In one embodiment, the controller 36 includes capacitor(s) 52 for storing a charge
received form a power source 54, in which the drive signal 40 is a single charge.
The signal charge from the controller 36 causes the incremental rotation of the ratcheting
mechanism 12 and lead screw 14. As mentioned previously above, this rotation advances
the plunger 48 into container 50 to dispense a predetermined volume of the drug out
of the drug container, such as for example, into the subcutaneous tissue of a patient.
A hard stop 56 is provided to ensure that the ratcheting mechanism 12 is incremental
rotated a desire amount with each contraction of the SMA wire 10. In this embodiment,
the hard stop 56 is also electrically connected to the controller, via electrical
conductor 58, and provides a motion feedback signal of the ratcheting mechanism 12.
In one embodiment, the hard stop 56 provides the controller 36 the motion feedback
signal upon a projection 60 provided by the second ratchet wheel 18 contacting the
hard stop 56 due to rotation of the ratcheting mechanism 12 in the first (drive) direction
D. In this manner, the hard stop 56 helps to provide accuracy in the dispensing of
the liquid drug since accurate displacement of the SMA wire 10 is very difficult to
achieve.
[0019] FIG. 2 shows another embodiment of a pump drive 200 according to the present invention
wherein the torsion spring 34 is not fixed between the second ratchet wheel 18 and
post 24 as in the previous embodiment illustrated by FIG. 1. In this alternative embodiment,
the second ratchet wheel 18 is rotated by the attached SMA wire 10 in the first (drive)
direction D and counter rotated in the second (reset) direction S by a reset spring
62. In this manner, the reset spring 62 takes over the function of the torsion spring
34 of applying the reset force R to the second ratchet wheel 18 to bring the SMA wire
10 back to the initial position after a contraction C. For brevity, as the pump drive
200 advances the plunger 48 in the same manner as described above with reference to
the pump drive 100 shown by FIG. 1, no further discussion is provided about this embodiment.
[0020] FIG. 3 shows still another embodiment of a pump drive 300 according to the present
invention. In this embodiment, the pump drive 300 comprises two ratchet wheels 16,
18 similar to the embodiment of FIG. 1, except that the SMA wire 10 is not directly
connected to the second ratchet wheel 18. In this alternative embodiment, the SMA
wire 10 is oriented parallel to the rotational axis X, instead of perpendicular as
in the previous embodiments, and directly connected to a side of a sliding mechanism
64. The reset spring 62 is connected to another side of the sliding mechanism 64 opposite
to the side to which the SMA wire 10 is attached, wherein the torsion spring 34 provides
the same function as provided in the embodiment shown by FIG. 2. In this manner, the
sliding mechanism 64 performs parallel reciprocating motion to the rotational axis
X upon contraction C of the SMA wire 10, and resetting via reset force R being provided
by the reset spring 62. This aligned configuration of the SMA wire 10, the reset spring
62, and sliding mechanism 64 allows a compact design since all parts are accommodated
close to the ratcheting mechanism 12 and lead screw 14.
[0021] To move the ratcheting mechanism 12, via the parallel reciprocating motion of the
sliding mechanism 64, the second ratchet wheel 18 provides a pin 66 that fits into
a S-curve shaped slot 68 of the sliding mechanism 64. The sliding mechanism 64 is
guided parallel to the rotational axis X and when the SMA wire 10 contracts, the sliding
mechanism 64 moves axially and the S-curve shaped slot 68 displaces the pin 66 angularly
about the rotational axis X. This motion results in an incremental rotation of the
ratchet wheels 16, 18 and lead screw 14 in the first direction D and therefore in
an incremental axial advancement of the threaded nut 42. For brevity, as the pump
drive 300 advances the plunger 48 in the same manner as described above with reference
to the pump drive 100 shown by FIG. 1, no further discussion is provided about this
embodiment.
[0022] Another embodiment of a pump drive 400 according to the present invention is shown
by FIG. 4, with the same basic arrangement as the embodiment shown by FIG. 2, except
for the use of the facing ratcheting surfaces 20 and 22, the post 24, and the torsion
spring 34. In this embodiment, the first ratchet wheel 16 is provided with an insert
portion 70 providing radially flexible teeth, generally indicated by symbol 72, and
the second ratchet wheel 18 is provided as a sleeve having rigid teeth, generally
indicated by symbol 74, provided radially on an interior surface thereof. In an alternative
embodiment, the flexible teeth 72 may be provided to the second ratchet wheel 18 and
the rigid teeth 74 may be provided to the insert portion 70 of the first ratchet wheel
16.
[0023] As shown, the insert portion 70 is accommodated in the second ratchet wheel 18 such
that the flexible teeth 72 is engaged by the rigid teeth 74 when the second ratchet
wheel is rotated in the first (drive) direction D, and the rigid teeth 74 will slip
pass the flexible teeth 72 when the second ratchet wheel 18 is rotated in the opposite
direction via the resetting force R provided by reset spring 62 after a contraction
C of the SMA wire 10. An end cap 76 is mounted rotatably to an end of the insert portion
70 adjacent the second ratchet wheel 18 on the side opposed to the first ratchet wheel
16, to maintain the teeth 72, 74 in axial alignment along the rotational axis X. For
brevity, as the pump drive 400 advances the plunger 48 in the same manner as described
above with reference to the pump drive 200 shown by FIG. 2, no further discussion
is provided about this embodiment.
[0024] In all the illustrative pump drive embodiments shown by FIGS. 1-4, the power source
54 is a battery provided to power the infusion pump 32. The power source (i.e., battery)
54 is held between a pair of electrical terminal posts 78 which are wired to provide
power to the controller 36. Other electrical component, such as for example, an on/off
button 90 (FIG. 5) and a small/large dose selection switch 92 (FIG. 5) may also be
provided as input to the controller 36 to provide the stated function to the infusion
pump 32.
[0025] As shown by FIG. 5, a pump drive 500 according to any one of embodiments of the pump
drive 100, 200, 300, and 400 shown by FIGS. 1-4, is conveniently used in a miniature
drug delivery pump 128. In the illustrated embodiment, the power source 54 is a battery,
such as for example a size AAAA, which is about 42.5 mm long and about 8.3 mm in diameter,
weighing around 6.5 grams. Output of alkaline batteries in this size is about 1.5
volts, 625 mA•h. Although elements in the figures may be exaggerated in portion to
other components, it is to be appreciated that the approximate relative size between
the drug deliver pump 128 and the battery is intended to be shown in the embodiment
illustrated by FIG. 5. Accordingly, as shown, the miniature drug deliver pump 128
is not much larger than the AAAA battery, and is in one embodiment about 61 mm long,
about 32 mm wide, and 15.5 mm in height, and weighs about 32 grams, with the container
50 holding about 2 ml of a liquid drug. Such dimensions of the drug deliver pump 128
is about one third the size of existing conventional drug deliver pumps. The small
size of the drug delivery pump 128 due to the reduction in size and components of
the pump drive 500 as well as the drive's silent operation, makes it easier for the
patient to conceal the drug deliver pump under clothing.
[0026] In the illustrated embodiment shown by FIG. 5, the drug delivery pump 128 provides
a scaled window 94 through which a portion of plunger 48 is visible and by which the
patient may use to meter/monitor the delivery of the liquid drug from the container
50. The container 50 includes an injection site 96 which is used to connect a spike
connector 98 of an administration set 102 to the drug deliver pump 128. The spike
connector 98 is connected to a fluid conduit 104 which at the distal end connects
to a catheter 106, which enters the patient's intravenous system through the skin
for delivery of the liquid drug.
[0027] Although not limited to, some of the noted advantages of the present invention are
as follows: the inherent precision of the motion from the shape memory alloy wire
actuator arrangement which can be used to accurately deliver very small doses (i.e.,
about 100 nL), nearly silent operation, fewer moving parts, and smaller parts. Such
advantages result in an overall compact and low cost drug delivery pump for the consumer.
[0028] The foregoing description of the invention has been presented for purposes of illustration
and description. It is not intended to be exhaustive or to limit the invention to
the precise form disclosed, and other modifications and variations may be possible
in light of the above teachings. The above embodiments disclosed were chosen and described
to explain the principles of the invention and its practical application to thereby
enable others skilled in the art to best utilize the invention. It is intended that
the appended claims be construed to include other alternative embodiments of the invention
except insofar as limited by the prior art.
1. A drive system (100, 200, 300, 400, 500) used to dispense a liquid drug from a drug
container (50) having a plunger (48), said drive system comprising: a lead screw (14)
having a rotational axis (X) and being operably connected to the plunger; a ratcheting
mechanism (12) having a first ratchet wheel (16) that is connected to the lead screw
(14), to move the lead screw; and a shape memory alloy wire (10) operably connected
to the ratchet mechanism (12); wherein the shape memory alloy wire is configured to
actuate the ratchet mechanism (12) via contraction (C) of the wire, which in turn
incrementally drives the rotation of the first ratchet wheel (16) about the rotational
axis (X) in a first drive direction (D), thereby moving the lead screw (14) and advancing
the plunger (48) to dispense the liquid drug from the drug container (50), wherein
the drive system (100, 200, 300, 400, 500) includes a torsion spring (34) or a reset
spring (62) to reset (R) the shape memory alloy wire (10) after contraction (C),
characterized in that the ratchet mechanism (12) comprises a second ratchet wheel (18), wherein the first
and second ratchet wheels (16, 18) are provided along the rotational axis (X) and
arranged perpendicularly to the lead screw (14); the first and second ratchet wheels
(16, 18) provide two opposing ratcheting surfaces (20, 22) with facing teeth that
are spring biased for proper engagement; and the shape memory alloy wire (10) is operably
connected to the second ratchet wheel (18) and configured to drive the rotation of
the second ratchet wheel (18) in the first drive direction (D).
2. The drive system according to claim 1, characterized in that the two opposing ratcheting surfaces (20, 22) of the first and second ratchet wheels
(16, 18) are provided perpendicular to the rotational axis (X).
3. The drive system according to claim 1 or 2, characterized in that the two opposing ratcheting surfaces (20, 22) of the first and second ratchet wheels
(16, 18) are spring biased for proper engagement via a spring (34).
4. The drive system according to any of claims 1 to 3, characterized in that the shape memory alloy wire (10) is oriented perpendicularly to the rotation axis
(X).
5. The drive system according to any of claims 1 to 4, characterized by a post (24) about which the first and second ratchet wheels (16, 18) are mounted
rotatably, wherein the second ratchet wheel (18) is spring biased axially (Z) on the
post (24) towards the first ratchet wheel (16) via a spring (34).
6. The drive system according to claim 3 to 5, characterized in that the spring is a torsion spring (34).
7. The drive system according to claim 6, characterized in that the spring (34) is also used to reset (R) the second ratchet wheel (18) and the shape
memory alloy wire (10) after contraction (C).
8. The drive system according to claim any of claims 3 to 7, characterized by a post (24) about which the first and second ratchet wheels (16, 18) are mounted
rotatably, wherein the second ratchet wheel (18) is spring biased axially (Z) on the
post (24) towards the first ratchet wheel (16) via a torsion spring (34), the torsion
spring having a first end mounted to the second ratchet wheel (18) and a second end
mounted to the post (24), wherein the torsion spring is configured to reset (R) the
shape memory alloy wire (10) after contraction (C).
9. The drive system according to claim 1, characterized in that the first and second ratchet wheels (16, 18) provide two opposing ratcheting surfaces
having radially extending teeth (72, 74) that face each other, wherein one set of
teeth is flexible, and the other set of teeth are rigid.
10. The drive system according to any of claims 1 to 6, characterized by a sliding mechanism (64) having an S-curve shaped slot (68) with a portion angled
in regard to the rotation axis, wherein a pin (66) connected the second ratchet wheel
(18) is arranged in said slot (68), and the shaped memory alloy wire (10) is configured
to drive (C) the sliding mechanism parallel to the rotational axis (X), such that
the slot (68) angularly displaces the pin (66) about the rotation axis (X), thereby
driving the rotation of the second ratchet wheel (18) in a first drive direction (D).
11. A battery operated drug delivery device, the drug delivery device providing the drug
container, with a drive system (100, 200, 300, 400, 500) according to any of the preceding
claims.
1. Antriebssystem (100, 200, 300, 400, 500), das verwendet wird, um ein flüssiges Medikament
aus einem Medikamentenbehälter (50), der einen Kolben (48) aufweist, abzugeben, wobei
das Antriebssystem umfasst: eine Leitspindel (14), die eine Rotationsachse (X) aufweist
und mit dem Kolben betriebsfähig verbunden ist; einen Sperrklinkenmechanismus (12),
der ein erstes Sperrklinkenrad (16) aufweist, das mit der Leitspindel (14) verbunden
ist, um die Leitspindel zu bewegen; und einen Formgedächtnislegierungsdraht (10),
der mit dem Sperrklinkenmechanismus (12) betriebsfähig verbunden ist; wobei der Formgedächtnislegierungsdraht
ausgestaltet ist, um durch Zusammenziehen (C) des Drahts den Sperrklinkenmechanismus
(12) zu betätigen, was wiederum stufenweise die Rotation des ersten Sperrklinkenrads
(16) um die Rotationsachse (X) in eine erste Antriebsrichtung (D) antreibt, wodurch
die Leitspindel (14) bewegt wird und der Kolben (48) vorgeschoben wird, um das flüssige
Medikament aus dem Medikamentenbehälter (50) abzugeben, wobei das Antriebssystem (100,
200, 300, 400, 500) eine Torsionsfeder (34) oder eine Rückstellfeder (62) enthält,
um den Formgedächtnislegierungsdraht (10) nach dem Zusammenziehen (C) rückzustellen,
dadurch gekennzeichnet, dass der Sperrklinkenmechanismus (12) ein zweites Sperrklinkenrad (18) umfasst, wobei
das erste und das zweite Sperrklinkenrad (16, 18) entlang der Rotationsachse (X) vorgesehen
sind und senkrecht zur Leitspindel (14) angeordnet sind; das erste und das zweite
Sperrklinkenrad (16, 18) zwei gegenüberliegende Sperrflächen (20, 22) mit zugewandten
Zähnen, die für einen richtigen Eingriff federbelastet sind, bereitstellen; und der
Formgedächtnislegierungsdraht (10) mit dem zweiten Sperrklinkenrad (18) betriebsfähig
verbunden ist und ausgestaltet ist, um die Rotation des zweiten Sperrklinkenrads (18)
in der ersten Antriebsrichtung (D) anzutreiben.
2. Antriebssystem nach Anspruch 1, dadurch gekennzeichnet, dass die zwei gegenüberliegenden Sperrflächen (20, 22) des ersten und des zweiten Sperrklinkenrads
(16, 18) senkrecht zur Rotationsachse (X) vorgesehen sind.
3. Antriebssystem nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass die zwei gegenüberliegenden Sperrflächen (20, 22) des ersten und des zweiten Sperrklinkenrads
(16, 18) für einen richtigen Eingriff durch eine Feder (34) federbelastet sind.
4. Antriebssystem nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, dass der Formgedächtnislegierungsdraht (10) senkrecht zur Rotationsachse (X) ausgelegt
ist.
5. Antriebssystem nach einem der Ansprüche 1 bis 4, gekennzeichnet durch eine Stange (24), um welche das erste und das zweite Sperrklinkenrad (16, 18) rotierbar
befestigt sind, wobei das zweite Sperrklinkenrad (18) axial (Z) an der Stange (24)
zu dem ersten Sperrklinkenrad (16) hin durch eine Feder (34) federbelastet ist.
6. Antriebssystem nach Anspruch 3 bis 5, dadurch gekennzeichnet, dass die Feder eine Torsionsfeder (34) ist.
7. Antriebssystem nach Anspruch 6, dadurch gekennzeichnet, dass die Feder (34) auch verwendet wird, um das zweite Sperrklinkenrad (18) und den Formgedächtnislegierungsdraht
(10) nach dem Zusammenziehen (C) rückzustellen (R).
8. Antriebssystem nach einem der Ansprüche 3 bis 7, gekennzeichnet durch eine Stange (24), um welche das erste und das zweite Sperrklinkenrad (16, 18) rotierbar
befestigt sind, wobei das zweite Sperrklinkenrad (18) axial (Z) an der Stange (24)
zu dem ersten Sperrklinkenrad (16) hin durch eine Torsionsfeder (34) federbelastet
ist, die Torsionsfeder ein erstes Ende, das an dem zweiten Sperrklinkenrad (18) befestigt
ist, und ein zweites Ende, das an der Stange (24) befestigt ist, aufweisend, wobei
die Torsionsfeder ausgestaltet ist, um den Formgedächtnislegierungsdraht (10) nach
dem Zusammenziehen (C) rückzustellen (R).
9. Antriebssystem nach Anspruch 1, dadurch gekennzeichnet, dass das erste und das zweite Sperrklinkenrad (16, 18) zwei gegenüberliegende Sperrflächen,
die sich radial erstreckende Zähne (72, 74) aufweisen und zueinander weisen, bereitstellen,
wobei ein Satz Zähne biegbar ist und der andere Satz Zähne starr ist.
10. Antriebssystem nach einem der Ansprüche 1 bis 6, gekennzeichnet durch einen Gleitmechanismus (64), der einen S-Kurven-förmigen Schlitz (68) mit einem Abschnitt,
der bezüglich der Rotationsachse abgewinkelt ist, aufweist, wobei ein Zapfen (66),
der mit dem zweiten Sperrklinkenrad (18) verbunden ist, in dem Schlitz (68) angeordnet
ist, und der Formgedächtnislegierungsdraht (10) ist ausgestaltet, um den Gleitmechanismus
parallel zur Rotationsachse (X) anzutreiben (C), derart, dass der Schlitz (68) den
Zapfen (66) um die Rotationsachse (X) winkelartig verschiebt, wodurch die Rotation
des zweiten Sperrklinkenrads (18) in einer ersten Antriebsrichtung (D) angetrieben
wird.
11. Batteriebetriebene Medikamentenabgabevorrichtung, wobei die Medikamentenabgabevorrichtung
den Medikamentenbehälter mit einem Antriebssystem (100, 200, 300, 400, 500) nach einem
der vorherstehenden Ansprüche bereitstellt.
1. Système d'entraînement (100, 200, 300, 400, 500) utilisé pour administrer un médicament
liquide à partir d'un contenant de médicament (50) ayant un piston (48), ledit système
d'entraînement comprenant : une vis-mère (14) ayant un axe de rotation (X) et reliée
de manière fonctionnelle au piston ; un mécanisme à cliquet (12) ayant une première
roue à cliquet (16) reliée à la vis-mère (14) pour faire bouger la vis-mère ; et un
fil d'alliage à mémoire de forme (10) relié de manière fonctionnelle au mécanisme
à cliquet (12); dans lequel le fil d'alliage à mémoire de forme est configuré pour
actionner le mécanisme à cliquet (12) via une contraction (C) du fil, ce qui entraîne
à son tour de façon incrémentielle la rotation de la première roue à cliquet (16)
autour de l'axe de rotation (X) dans une première direction d'entraînement (D) en
faisant bouger de la sorte la vis-mère (14) et avancer le piston (48) pour administrer
le médicament liquide à partir du contenant de médicament (50), dans lequel le système
d'entraînement (100, 200, 300, 400, 500) comprend un ressort de torsion (34) ou un
ressort de rappel (62) pour remettre à l'état initial (R) le fil d'alliage à mémoire
de forme (10) après la contraction (C),
caractérisé en ce que le mécanisme à cliquet (12) comprend une deuxième roue à cliquet (18), dans lequel
les première et deuxième roues à cliquet (16, 18) sont fournies le long de l'axe de
rotation (X) et disposées perpendiculairement à la vis-mère (14); les première et
deuxième roues à cliquet (16, 18) fournissent deux surfaces d'encliquetage (20, 22)
opposées avec des dents se faisant face qui sont sollicitées par ressort pour la mise
en prise correcte; et le fil d'alliage à mémoire de forme (10) est relié de manière
fonctionnelle à la deuxième roue à cliquet (18) et est configuré pour entraîner la
rotation de la deuxième roue à cliquet (18) dans la première direction d'entraînement
(D).
2. Système d'entraînement selon la revendication 1, caractérisé en ce que les deux surfaces d'encliquetage opposées (20, 22) des première et deuxième roues
à cliquet (16, 18), sont fournies perpendiculairement à l'axe de rotation (X).
3. Système d'entraînement selon la revendication 1 ou 2, caractérisé en ce que les deux surfaces d'encliquetage opposées (20, 22) des première et deuxième roues
à cliquet (16, 18) sont sollicitées par ressort pour la mise en prise correcte via
un ressort (34).
4. Système d'entraînement selon l'une quelconque des revendications 1 à 3, caractérisé en ce que le fil d'alliage à mémoire de forme (10) est orienté perpendiculairement à l'axe
de rotation (X).
5. Système d'entraînement selon l'une quelconque des revendications 1 à 4, caractérisé par une colonne (24) autour de laquelle les première et deuxième roues à cliquet (16,
18) sont montées rotativement, dans lequel la deuxième roue à cliquet (18) est sollicitée
axialement par ressort (Z) sur la colonne (24) vers la première roue à cliquet (16)
via un ressort (34).
6. Système d'entraînement selon les revendications 3 à 5, caractérisé en ce que le ressort est un ressort de torsion (34).
7. Système d'entraînement selon la revendication 6, caractérisé en ce que le ressort (34) est également utilisé pour remettre à l'état initial (R) la deuxième
roue à cliquet (18) et le fil d'alliage à mémoire de forme (10) après la contraction
(C).
8. Système d'entraînement selon l'une quelconque des revendications 3 à 7, caractérisé par une colonne (24) autour de laquelle les première et deuxième roues à cliquet (16,
18) sont montées rotativement, dans lequel la deuxième roue à cliquet (18) est sollicitée
axialement par ressort (Z) sur la colonne (24) vers la première roue à cliquet (16)
via un ressort de torsion (34), le ressort de torsion ayant une première extrémité
montée sur la deuxième roue à cliquet (18) et une deuxième extrémité montée sur la
colonne (24), dans lequel le ressort de torsion est configuré pour remettre à l'état
initial (R) le fil d'alliage à mémoire de forme (10) après la contraction (c).
9. Système d'entraînement selon la revendication 1, caractérisé en ce que les première et deuxième roues à cliquet (16, 18) fournissent deux surfaces d'encliquetage
opposées ayant des dents s'étendant radialement (72, 74) qui se font face les unes
les autres, dans lequel un ensemble de dents est flexible et l'autre ensemble de dents
est rigide.
10. Système d'entraînement selon l'une quelconque des revendications 1 à 6, caractérisé par un mécanisme de coulissement (64) ayant une fente en forme de courbe en S (68) avec
une partie en angle compte tenu de l'axe de rotation, dans lequel un ergot (66) relié
à la deuxième roue à cliquet (18) est disposé dans ladite fente (68), et le fil d'alliage
à mémoire de forme (10) est configuré pour entraîner (C) le mécanisme de coulissement
parallèlement à l'axe de rotation (R) de sorte que la fente (68) déplace l'ergot (66)
de façon angulaire autour de l'axe de rotation (X) en entraînant de la sorte la rotation
de la deuxième roue à cliquet (18) dans une première direction d'entraînement (D).
11. Dispositif d'administration de médicaments fonctionnant sur piles, le dispositif d'administration
de médicaments fournissant le contenant de médicament, avec un système d'entraînement
(100, 200, 300, 400, 500) selon l'une quelconque des revendications précédentes.
REFERENCES CITED IN THE DESCRIPTION
This list of references cited by the applicant is for the reader's convenience only.
It does not form part of the European patent document. Even though great care has
been taken in compiling the references, errors or omissions cannot be excluded and
the EPO disclaims all liability in this regard.
Patent documents cited in the description